Dynamic Covalent Dextran Hydrogels as Injectable, Self-adjuvating Peptide Vaccine Depots

Dextran-based hydrogels are promising therapeutic materials for drug delivery, tissue regeneration devices, and cell therapy vectors, due to their high biocompatibility, along with their ability to protect and release active therapeutic agents. This report describes the synthesis, characterization and application of a new dynamic covalent dextran hydrogel as an injectable depot for peptide vaccines. Dynamic covalent crosslinks based on double Michael addition of thiols to alkynones impart the dextran hydrogel with shear-thinning and self-healing capabilities, enabling hydrogel injection. These injectable, non-toxic hydrogels show adjuvant potential and have predictable sub-millimolar loading and release of the peptide antigen SIINFEKL, which after its release is able to activate T-cells, demonstrating that the hydrogels deliver peptides without modifying their immunogenicity. This work demonstrates the potential of dynamic covalent dextran hydrogels as a sustained-release material for delivery of peptide vaccines.

Protective Effect of Dinitrosyl Iron Complexes Bound with Hemoglobin on Oxidative Modification by Peroxynitrite

Dinitrosyl iron complexes (DNICs) are a physiological form of nitric oxide (•NO) in an organism. They are able not only to deposit and transport •NO, but are also to act as antioxidant and antiradical agents. However, the mechanics of hemoglobin-bound DNICs (Hb-DNICs) protecting Hb against peroxynitrite-caused, mediated oxidative modification have not yet been scrutinized. Through EPR spectroscopy we show that Hb-DNICs are destroyed under the peroxynitrite action in a dose-dependent manner. At the same time, DNICs inhibit the oxidation of tryptophan and tyrosine residues and formation of carbonyl derivatives. They also prevent the formation of covalent crosslinks between Hb subunits and degradation of a heme group. These effects can arise from the oxoferryl heme form being reduced, and they can be connected with the ability of DNICs to directly intercept peroxynitrite and free radicals, which emerge due to its homolysis. These data show that DNICs may ensure protection from myocardial ischemia.

Innovative Water-Insoluble Edible Film Based on Biocatalytic Crosslink of Gelatin Rich in Glutamine

Gelatin is a promising candidate for making bioplastic film; however, the water soluble property has limited its applications. Here, we have successfully fabricated a water-insoluble gelatin film with the assistance of biocatalysis. This innovative gelatin film could retain its original shape at ambient temperature (30 °C) or even in boiling water. Type E gelatin could form more covalent crosslinks when compared to that of conventional ones with the same amount of microbial transglutaminase (MTGase), and it exhibits obvious changes in terms of molecular weight, network structure, and mechanical strength. This work could provide a strategy for fabricating water-insoluble gelatin film and open routes for the development of bioplastic film using gelatin.

Allyl sulfide-based visible light-induced dynamically reshaped liquid crystalline elastomer/SWCNT nanocomposites capable of multimode NIR photomechanical actuations

The fully light-driven LCE/SWCNT composite films with exchangeable covalent crosslinks possess reconfigurability and recyclability, enabling shrinking, bending and curling motions.

Viscoelasticity of hydrazone crosslinked poly(ethylene glycol) hydrogels directs chondrocyte morphology during mechanical deformation

Adaptable dynamic covalent crosslinks temporally modulate the biophysical transmission of physiologically relevant compressive strains to encapsulated chondrocytes for cartilage tissue engineering.